1. Cleveland Clinic, Cleveland, Ohio, USA
2. Yale School of Medicine, New Haven, Connecticut, USA
3. Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
4. Medical University of South Carolina, Charleston, South Carolina, USA
5. University of Vermont Medical Center, Burlington, Vermont, USA
6. Washington University, St. Louis, Missouri, USA
7. Mayo Clinic, Rochester, Minnesota, USA